Abstract
The protein kinase A pathway and the cyclic AMP-response element
binding protein (CREB) appear to play a critical role in the
consolidation of short-term changes in neuronal activity into
long-term memory storage in a variety of systems ranging from the
gill and siphon withrawal reflex in Aplysia to olfactory
conditioning in Drosophila to spatial and contextual
learning in mice. In this review we describe the molecular
machinery that mediates memory consolidation in each of these
systems. One of the surprising findings to emerge, particularly
from studies of long-term facilitation in Aplysia, is that
memory storage is mediated by not only positive but also negative
regulatory mechanisms, in much the same way as cell division is
controlled by the proteins encoded by oncogenes and tumor
suppressor genes. This suggests the interesting possibility that
there are memory suppressor genes whose protein products impede
memory shortage.